Fluid cooled, lubricated and sealed piston means for casting devices



June 7, 1966 G. R. MORTON 3,254,377

FLUID COOLED, LUBRICATED AND SEALED PISTON MEANS FOR CASTING DEVICESFiled April 22, 1963 lzV/f/VER 4259 6. 440670 Is /7405515 5:WORMEAIMfiV/SJ Illa/ 9 VS UIIIECG 31:31:68 f2lII1II UH1C 3,254,377 FLUIDCOOLED, LUBRICATED AND SEALED PIS- TON MEANS FOR CASTING DEVICES GlennR. Morton, 7025 Sarpy Ave., Omaha, Nebr. Filed Apr. 22, 1963, Ser. No.282,827 3 Claims. (Cl. 22-68) This invention relates to casting machinesand more particularly to a means for cooling, lubricating and sealingthe material injecting means, such as the short piston and cylinder orcompression piston and cylinder of a casting device. This is acontinuation in part of my application Serial Number 53,704 filedSeptember 2, 1960, now abandoned.

The casting of objects and parts is very old but many apparatusrefinements in the art have been made in recent years. Today, it isquite common to produce at least a semi-vacuum condition in the moldcavity prior to the introduction of the molten material. Also, in mostsuch casting equipment, the molten material is pressure forced into themold cavity by a piston means. The piston may be reciprocatively mountedin a shot cylinder, or it may be in the form of at least a part of oneside of the mold cavity as shown in FIGURE 1. However, regardless of thefunction, or design of the cylinder and piston, much difficulty isexperienced in the objectionable heating of the piston, the properlubricating of the piston, and the leakage of the molten material andeven air past the piston.

Therefore, one of the principal objects of my invention is to provide amethod of and means for lubricating and cooling the injection and/orcompressing piston of a casting device.

More specifically the object of my invention is to surround thereciprocating piston means with a changing mote of fluid such as alubricating oil.

A still further object of this invention is to provide an oil sealedpiston means for casting machines.

Still further objects of my invention are to provide a method of andmeans for conditioning the piston means of a casting machine that iseconomical in manufacture and durable in use.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangements, andcombination, of the various parts of the device, whereby the objectscontemplated are attained as hereinafter more fully set forth,specifically pointed out in my claims, and illustrated in theaccompanying drawing, in which:

FIGURE 1 is a side sectional view of a casting machine using my pistonconditioned means, and

FIGURE 2 is a cross sectional view of the device taken on line 2-2 ofFIGURE 1, and more fully illustrates its construction.

In the drawing I have used the numeral to designate one side of a moldblock. The second mold block is generally designated by the numeral 11.These two blocks are separable for the purpose of discharging thesolidified casting but are detachably held together by any suitablemeans during the actual casting phase. The adjacent faces of the blocksare cut away to provide, when the blocks are secured together, the moldcavity 12. Communicating with the mold cavity is a conduit 13 adapted tobe in communication with a suction producing means (not shown). In theblock 11 is formed a relatively large vertical cylinder or passageway 16communicating with and forming a part of the mold cavity as shown inFIGURE 1. Slidably mounted in this cylindrical portion 16 is a verticalpiston ram 17 having its top surface forming at least a portion of theunder side of the mold cavity 12. This member 17 may be powerreciprocated by any suitable means. In the drawing I show a poweredcrank shaft 19 and a connecting rod 20 having one end rotatably mountedon the crank arm 19 and its other end hingedly secured to the bottom ofthe member 17. By this arrangement of parts at least a part of one sideor face of the mold cavity will be movable. The numeral 21 designatedthe molten material inlet conduit communicating with the inside of thecylinder 16 at a point between the extreme movement of the piston member17 in both directions. Therefore, when the piston member 17 is in alowered position the conduit 21 will communicate directly with theinside of the cylinder 16 but when the piston 17 is elevated in itssliding movement, the point of communication between the conduit 21 andthe cylinder 16 will be closed by the side wall of the member 17. Thenumeral 22 designates a container having the molten material 23, andinto which the conduit 21 extends.

With the two mold sections 10 and 11 closed together and with the pistonram 17 held in a lowered position, the conduit 13 is opened therebyproducing a semivacuum within the mold cavity. Due to the minusatmospheric pressure within the mold cavity and the upper end of thecylinder 16, the molten material 23 will flow into the upper end of thecylinder 16 and mold cavity. After a suitable amount of the moltenmaterial has entered the mold the conduit 13 is closed and the pistonram 17 is moved upwardly to its maximum elevated position within thecylinder 16 as shown by broken lines in FIGURE 1. After the pressurizedcasting has cooled, the two mold halves are separated and the castingtaken therefrom.

The casting machine thus far disclosed is one example of an apparatus towhich I apply my invention and which I will now describe in detail.

As to the piston 17 I have an enlarged head portion 25 and a reducedrear end portion 26. The reduced lower or rear end of the pistonslidably extends through a close fitting gasket 27 at the lower or rearend of the cylinder 16, thereby creating a compartment 29 in the lowerarea of the cylinder and which surrounds the reduced area of the pistonbelow its head 25. In the cylinder wall and embracing the head 25 whenthe piston is in a lowered position in the cylinder, is a continuousgroove or mote 30. When the piston is in an elevated position in thecylinder, this mote groove will be in communication with the compartment29. The numeral 31 designates an oil supply tank adapted to contain oilor like 32. On top of the tank 31 is a relatively small oil return tank33. The numeral 35 designates a vertical pipe having one endcommunicating with the inside of the tank 33 above its inside bottom andits other end communicating with the inside of the tank 31. The top ofpipe 35 dwells above the bottom of tank 33. The numeral 36 designates aone-way valve for preventing fluid in the tank 31 from passing directlyinto the tank 33. A vacuum in tank 33 will normally hold valve 36closed, but an accumulation of oil in the tank will depress theball-spring component in the valve and the oil will move into tank 31.The numeral 37 designates a conduit having one end communicating withthe inside top of the tank 33 and its other end adapted to be incommunication with a Patented June 7, 1966 source of suction (notshown). The numeral 39 designates a solenoid valve imposed in theconduit 37. The numeral 40 designates a conduit having one endcommunicating with the compartment 29 and its other end communicatingwith the inside of the tank 33. The numeral 41 designates a conduithaving one end communicating with the mote grove 30 and its other endcommunicating with the inside bottom area of the tank 31. The numeral 42designates a one-way check valve for preventing liquid from returningfrom the conduit 41 back into the tank 31. The operation of my device isas follows:

Obviously, the movement and position of the piston may be timed orregulated with the normally closed solenoid valve 39. This can be donein several convenient ways. For example, a micro-switch (not shown) in anormally closed position can be held in an open position by the upperportion of crankshaft 19 as viewed in FIG- URE 1. The micro-switch canbe electrically connected to the solenoid valve 39 and thence to asource of electrical energy. Thus, when the top of the crankshaft 19moves downwardly from the position shown in FIG- URE l, the micro-switchcan move to a closed position to cause solenoid valve 39 to becomeelectrically excited and to open. A vacuum will then be pulling throughconduit 37, tank 33 and line 40 until the piston head is lowered and thecrankshaft 19 once again opens such a micro-switch to close valve 39.

When the piston 17 moves upwardly, the solenoid valve a 39 is opened inthe manner described and a vacuum is allowed to pull through conduit40.as indicated. This initially performs no function until thecompartment 29 has moved upwardly to register with mote 30 which servesto connect conduits 40 and 41. This allows the vacuum on conduit 40 tocreate a suction in conduit 41 (through compartment 29) which opensvalve 42 and brings oil from tank 31 into mote- 30 through conduit 41.The oil will thence move from the mote 30 into the compartment 29, andthence through the conduit into tank 33. As soon as the extreme lowerend portion 45 of piston 17 moves upwardly through gasket 27, thesuction on conduit 41 is broken and no more oil is pulled from tank 31.Similarly, all the oil in conduit 40 is pulled into tank 33 and thenonly atmospheric air moves into the conduit and moves toward tank 33 andvalve 39. No oil will move into the top of pipe 55, until the depth ofoil in tank 33 achieves the height of the top of the pipe. Thus, theaccumulation of oil in tank 33 permits it to cool before moving intotank 31. In addition, the air being pulled through tank 33 duringthisphase of the operation serves to further cool the oil. When the oilreaches a level in tank 33 to fill pipe 35, the weight of the oil willslightly depress the ball and spring in valve 36, and the cooled fluidwill then pass by gravity into tank 31. The tank 33 never becomes fullenough of fluid to permit fluid to be pulled towards valve 39 throughconduit 37. Normally, one cycle of piston 17 will not create a largeenough accumulation of fluid in tank 33 to permit oil to flow throughpipe 35 into tank 31.

Some oil will remain by adhesion in the mote 30 and will serve as an oilsupply to lubricate the piston 17. Also, before the vacuum is broken inthe manner described, the piston 17 will be surrounded by an oil bath incompartment 29. It is seen from the foregoing that the coordination ofvalve 39 with the remaining com ponents of my device is important onlyif the vacuum being pulled through conduit 37, tank 33 and line is notcontinuous. For purposes of efliciency of operating the source of thevacuum, it is desirable to close off the vacuum in line 37 by valve 39at least during part of the cycle. The vacuum must be pulling at thetimethat compartment 29 joins conduits 40 and 41, but any arrangementwhich will close valve 39 or otherwise relieve the vacuum on line 40after the lower end of the piston 17 breaks the vacuum in compartment 29will prove satisfactory. As noted above, the pulling of atmospheric airthrough tank 33 after the vacuum is broken does serve the beneficialresult of cooling the oil in the tank. It should be further noted thatthe pilling of oil from tank 31, through conduit 41, mote 30,compartment 29, conduit 40 and into tank 33 while the vacuum is ineffect is an impulse and momentary phenomenon that takes place only onceeach cycle of piston 17, and which moves only a nominal amount of oilduring this brief portion of the cycle.

Some changes may be made in the construction and arrangement of my fluidcooled, lubricated and sealed piston means for casting devices withoutdeparting from the real spirit and purpose of my invention, and it is myintention to cover by my claims, any modified forms of structure or useof mechanical equivalents which may be reasonably included within theirscope.

I claim:

1. In combination,

a cylinder,

a reciprocating piston in said cylinder,

a recessed portion in said piston to create a compartment between saidpiston and the interior of said cylinder,

conduits leading to and from the interior of said cylinder,

said compartment having a size to communicate with said conduits at oneportion of said pistons reciprocating path in said cylinder,

means operatively secured to said conduits for circulating a fluid intosaid cylinder from one conduit and withdrawing said fluid therefromthrough said other conduit,

said one of said conduits being connected to a vacuum source, the otherof said conduits being connected to a source of fluid,

and means on said piston for exposing said compartment to the atmosphereat one stage of its reciprocal movement. a

2. In combination,

a cylinder,

a reciprocating piston in said cylinder,

a recessed portion in said piston to create a compartment between saidpiston and the interior of said cylinder,

conduits leading to and from the interior of said cylinder,

said compartment having a size to communicate with said conduits at oneportion of said pistons reciprocating path in said cylinder,

means operatively secured to said conduits for circulating a fluid intosaid cylinder from one conduit and withdrawing said fluid therefromthrough said other conduit,

one of said conduits being connected to a vacuum source, and the otherof said conduits being connected to a source of fluid,

a fluid cooling chamber being imposed in said firstment between saidpiston and the interior of said cylinder,

conduits leading to and from the interior of said cylinder,

said compartment having :1 size to communicate with said conduits at oneportion of said pistons reciprocating path in said cylinder,

means operatively secured to said conduits for circulating a fluid intosaid cylinder from one conduit and Withdrawing said fluid therefromthrough said other conduit,

said cylinder communicating with a mold cavity between two moldedblocks,

and molten liquid intake conduit being in communication with saidcylinder.

6 References Cited by the Examiner UNITED STATES PATENTS 543,165 7/1895Weiss 123192 1,001,306 8/1911 RiX 18418 3,029,752 4/ 1962 Frank 107-17J. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner.

1. IN COMBINATION, A CYLINDRICAL, A RECIRPOCATING PISTON IN SAIDCYLINDER, A RECESSED PORTION IN SAID PISTON TO CREATE A COMPARTMENTBETWEEN SAID PISTON AND THE INTERIOR OF SAID CYLINDER, CONDUITS LEADINGTO AND FROM THE INTERIOR OF SAID CYLINDER, SAID COMPARTMENT HAVING ASIZE TO COMMUNICATE WITH SAID CONDUITS AT ONE PORTION OF SAID PISTON''SRECIPROCATING PATH IN SAID CYLINDER, MEANS OPERATIVELY SECURED TO SAIDCONDUITS FOR CIRCULATING A FLUID INTO SAID CYLINDER FROM ONE CONDUIT ANDWITHDRAWING SAID FLUID THEREFROM THROUGH SAID OTHER CONDUIT, SAID ONE OFSAID CONDUITS BEING CONNECTED TO A VACUUM SOURCE, THE OTHER OF SAIDCONDUITS BEING CONNECTED TO A SOURCE OF FLUID, AND MEANS ON SAID PISTONFOR EXPOSING SAID COMPARTMENT TO THE ATMOSPHERE AT ONE STAGE OF ITSRECIPROCAL MOVEMENT.